Preparation of Mullite Nanocomposites Powders by the Hydrothermal Crystallization Method from Coal Gangue

Article Preview

Abstract:

Mullite nanocomposites powders have been successfully synthesized from pretreated coal gangue via hydrothermal crystallization process. The mullite nanocomposites powders are investigated and charactered by laser particle size analysis, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) analysis, selected area electron diffraction (SAED) analysis and energy-dispersive X-ray (EDX) analysis. Moreover, the reaction mechanism of this process is speculated according to MAS-NMR results. It is indicated that mullite nanocomposites powders can be prepared at 80-90 °C for 3 h with NaOH concentration of 2-4 mol/L and L/S ratio (liquid/solid ratio in mass) of 10 mL/g by using calcined coal gangue as precursor. The agglomerate powder size of D50 is about 3.83-4.71 mm. Furthermore, some imperfective puncheon-shaped crystals exist among a large number of whole puncheon-shaped crystals which are about 30-70 nm in length and about 10-20 nm in diameter. MAS-NMR analysis indicates that the nano-size mullite grow around the central atom-Al, Si of [AlSi]O4 tetrahedral and the growth unit Al[OH]4- exist in this process definitely.

You might also be interested in these eBooks

Info:

Periodical:

Key Engineering Materials (Volumes 512-515)

Pages:

49-53

Citation:

Online since:

June 2012

Export:

Price:

[1] B.M. Kim, Y.K. Cho, S.Y. Yoon, R. Stevens, H.C. Park, Mullite whiskers derived from kaolin, Ceram. Int. 35 (2009) 579.

DOI: 10.1016/j.ceramint.2008.01.017

Google Scholar

[2] J. S. Jung, H. C. Park and R. Stevens, Mullite ceramics derived from coal fly ash, J. Mater. Sci. Lett. 20 (2001) 1089.

Google Scholar

[3] S. Gustafsson, L.K.L. Falk, J.E. Pitchford, et al., Development of microstructure during creep of polycrystalline mullite and a nanocomposite mullite/5 vol.% SiC, J. Eur. Ceram. Soc. 29 (2009) 539.

DOI: 10.1016/j.jeurceramsoc.2008.06.036

Google Scholar

[4] N.C. Chen, D. Chen and D. Dong, Syntheses of mullite nanocomposites by the open-system hydrothermal crystallization methhod under normal pressure, J. Chin. Ceram. Soc. 34 (2006) 975.

Google Scholar

[5] N.C. Chen, D. Chen, W.X. Xu, F.P. Xu, Effective factors in preparation for multi-phase mullite nanocrystals by the normal pressure open-system hydro-thermal reaction, J. Chin. Ceram. Soc. 35 (2007) 101.

Google Scholar

[6] H.M. Ao and N.C. Chen, Study on Mullite Nanopowder with Hydrothermal Method from Natural Kaolin, Non-Metallic Mines. 31 (2008) 12.

Google Scholar

[7] N.C. Chen and D. Chen, Mullite Composite phase nanocrystalline from high-silica kaolin under normal pressure and temperature: An experimental study, K. Eng. Mater. 280-283 (2005) 1157.

DOI: 10.4028/www.scientific.net/kem.280-283.1157

Google Scholar

[8] D. Jia, Y.Y. Wang, Y.L. Ma, F. Gao, Application design of supercritical fluid ext raction column and its theory study, IM &P. 03 (2005) 10.

Google Scholar

[9] Y.Y. Wang, Z. Ma and Y.N. Qin, Preparation, characterization and properties of major phases mullite composite nanocrystals, Chin. J. Chem. Phys. 14,02(2001) 216.

Google Scholar

[10] L.X. Tong, J.H. Li, J. Shen, X.Q. Jiang, Preparation of mullite nanocomposites powders from coal fly ash via Hydrothermal Crystallization, Adv. Mater. Res. 250-253 (2011) 3313.

DOI: 10.4028/www.scientific.net/amr.250-253.3313

Google Scholar

[11] W. Guo, D.X. Li, J.H. Chen, et al., Changes in Mineral Composition and Structure of Coal Gangue During Heat Activation, J. Mater. Sci. & Eng. 26(2008) 204.

Google Scholar

[12] X.H. Zhang, H.S. Luo and W.Z. Zhong, Anion Coordination Polthedron Growth Unit Theory Mode and it's application in the crystal growth, Sci. Chin. Ser. E Tech. Sci. 34 (2004) 241.

Google Scholar

[13] W.J. Li, E.W. Shi, W.Z. Zhong, Z.W. Yin, Anion Coordination Polthedron Growth Unit Theory Mode and Crystal Morphology, J. Cryst. Growth. 203 (1999) 186.

Google Scholar